The Automatic Pistol Or The Revolver?

Which is better? And which is more powerful?

"Your Mileage May Vary" about sums it up.

As for power? That would depend on the round fired.
I just prefer high caliber (.357 or .44) revolvers because they have way more stopping power than 9 mil round, and are more dependable too.
Do they make a 9 mil revolver?
That would be one worthless weapon IMO.

Revolver or Rubber Soul?

Well, it's not what you were asking for exactly, but .38 is 9mm metrically.

I'll take my 9mm Ruger. It may not have the stopping power of the .357 or .44 magnum, but it holds 15 rounds compared to the six of those other guns. Plus, put hydroshock hollowpoints in the fucker and it would certainly ruin your day.

"One's all you need..."

Both.

9mm - more ammo

.45 ACP is your friend, unless it's pointed at you.

For 15 zombies, sure.

If I can only have one, then the automatic pistol, definitely. Preferably a 1911 or a Glock in .45 caliber.

If you can't solve it with a .45, it's probably not a problem you should be looking to a handgun for as a solution.

Correction, if you can't solve it with .45ACP, you go to .45-70Govt carrying a solid kinetic energy penetrator.

Wonder what shooting one of those of out of one of these would be like...

They do, and I'm sure it is.
Some .38/.357 revolvers have 9mm cylinders available. You have to use the cartridges held together with half-moon clips. Same for .45 auto - cylinders are made to fit in .45 colt revolvers.

The purpose being to shoot cheap mil surplus ammo in your revolver.

Here ya go.

Ah, but a .38 caliber bullet is .357" diameter, and a 9mm is .355"!

The "which is more powerful" question always up for grabs, but some of those crazy-ass .45-70 revolvers like paladin posted probably take the cake. I've seen semi-autos chambered for .50 cal rounds, but they're always short-cased pistol rounds, way shy of the .45-70.

And there are single-shot pistols available in pretty much any caliber on up to .600 Nitro Express.

The .500 Smith and Wesson Magnum pretty much takes the cake in terms of powerful revolvers.

However, if a revolver like the BFR could digest Elwood's "whammy" loads without splitting a cylinder, that would be about the most powerful handheld package you could buy. Or that you'd want. Recoil is going to be a very serious issue...

I like the youtube footage of the guy shooting the .600 NE revolver: it goes flying out of his hands! Waaaaaaaaaaaaaaaaaaay too much power to be usable in a handgun.

Again, 1911 in 10mm is the handgun God himself uses.

Semi-auto in right, revolver in left. Preferably with the pistol cocked in gangsta fashion.

I like to think of my Glock 20 10mm with full-power loads as being a 15 shot .357 Magnum.

Pthbtpthbtpthbtpthbtttttttt!

Definitely revolver, no tell tale expended rounds left behind to worry about later.

^That's a consideration.

My carry piece.

The Gun John Moses Browning designed in the round he designed it for.

If you have no mechanical skills at all, you're likely better off with a revolver. These also have the most powerful rounds, as there are no recoil springs/gas porting issues with the trusty old six-shooter.

Gas porting issues?

'cept for that whole thing about blowing apart on the shooter.

Seriously, if you're gonna shoot a couple hundred rounds through it a year and carry it concealed, I'm sure it's a fine weapon, but I've talked to more than one shooter that puts thousands of rounds through weapons per month and the 1911 design just can't hold up to those kinds of pressures without substantial reinforcements which alter the size and weight of the weapon, destroying it's classic pointability.

It's just a simple matter of physics because even if you put a freakin' huge recoil spring it in, the pressure is just so much higher it beats the gun to death.

230gr JHP in .45ACP = 19,600 PSI / 16,800 CUP
180gr JHP in 10mm Auto = 36,400 PSI / 32,200 CUP

Figures courtesy of Hodgdon's 2007 Reloading Manual